Thermoplastic resin composition

ABSTRACT

A novel thermoplastic resin composition excellent in heat resistance, impact resistance, hardness is provided which comprises 100 parts by weight of a composition comprising (A) 5-95% by weight of a polyphenylene ether prepared by oxidation polymerization of at least one phenol compound represented by the formula: ##STR1## wherein R 1 , R 2 , R 3 , R 4  and R 5  which may be identical or different and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon residue, with a proviso that at least one of them is a hydrogen atom and (B) 95-5% by weight of a polyamide and 5-100 parts by weight of (C) a copolymer of an ethylene-α-olefin copolymer rubber with an alkenyl aromatic compound and an unsaturated carboxylic acid or its anhydride. This composition may further contain 0.01-30 parts by weight of an epoxy compound (D) for 100 parts by weight of the composition of (A) and (B).

This is a division of application Ser. No. 07/113,471, filed Oct. 28,1987, now abandoned.

This invention relates to a resin composition comprising a polyphenyleneether and a polyamide.

More particularly, it relates to a novel thermoplastic resin compositionsuperior in heat resistance, mechanical properties and processabilitywhich comprises a resin composition comprising a polyphenylene ether anda polyamide, to which is added a copolymer of an ethylene-α-olefincopolymer rubber, an alkenyl aromatic compound and an unsaturatedcarboxylic acid or its anhydride or to which is further added an epoxycompound.

The composition of this invention is utilized as shaped articles, sheetsor films made by injection molding and extrusion molding.

Polyphenylene ether is a thermoplastic resin superior in variousmechanical properties, heat resistance, electrical properties, chemicalresistance, hot water resistance, flame resistance and dimensionstability, but inferior in processability due to high melt viscosity andrelatively inferior in impact resistance.

A composite material comprising polyphenylene ether and and polystyreneis proposed in order to lessen melt viscosity of polyphenylene ether andto improve processability thereof, leaving various other good propertiesof polyphenylene ether unchanged. However, such inherent good propertiesof polyphenylene ether as heat resistance, flame resistance and chemicalresistance are somewhat damaged when enough polystyrene is added toprovide practical processability. No sufficient improvement is seen inimpact resistance, either, even after polystyrene is added.

On the other hand, polyamide is a thermoplastic resin, characterized byits heat resistance, stiffness, strength, oil resistance, etc., butinferior in processability and impact resistance and besides high inwater absorption and great in changes of properties and dimension inpractical use. Thus, further improvements have been desired.

Development is expected in new applications if a resin composition isprepared in which polyphenylene ether and a polyamide are blended,maintaining favorite properties of both components and having improvedprocessability and impact strength. However, polyphenylene ether andpolyamide are greatly different in melt viscosity from each other andthey are very poor in compatibility. Simple, blending of them encountersthe following difficulties:

1. hardness in stable take-up of strands extruded and greatly lowerprocessability in molding, because their melt viscosity difference isvery large; and

2. no improvement in mechanical properties of the shaped articles,particularly in impact resistance, but rather lower than expected on thebasis of their respective values.

One approach to solve these problems is addition of additives havingreactivity of compatibility to system of polyphenylene ether andpolyamide as disclosed in Japanese Patent Publication (Kokoku) No.60-11966 and Japanese Patent Publication (Kokai) Nos, 56-47432, 57-10642and 60-58463. Especially, the methods disclosed in Japanese PatentPublication (Kokoku) No. 60-11966 and Japanese Patent Publication(Kokai) No. 56-47432 afford good effect, but impact strength is stillnot enough.

Furthermore, Japanese Patent Publication (kokai) Nos. 56-49753,57-10642, 57-165448 and 59-66452 disclose the use of reactive additiveswith modified polystyrene, polyphenylene ether or rubber. Suchcomposition is out of balance between impact resistance and heatresistance and besides improvement of impact resistance is still notsufficient.

After a study on a resin composition of polyphenylene ether andpolyamide, we have found that a resin composition high in fluidity whenmelted, namely, good in processability and having good balance betweenimpact strength and heat resistance is obtained by blending with acomposition comprising a polypenylene ether and a polyamide, a copolymerof ethylene-α-olefin copolymer rubber, an alkenyl aromatic compound andan unsaturated carboxylic acid or its anhydride or furthermore an epoxycompound.

That is, this invention relates to a thermoplastic resin compositionwhich comprises 100 parts by weight of a resin composition comprising(A) 5-95% by weight of a polyphenylene ether obtained by oxidationpolymerization of one or more phenol compounds represented by theformula: ##STR2## wherein R₁, R₂, R₃, R₄ and R₅ which may be identicalor different and represent a hydrogen atom, a halogen atom or asubstituted or unsubstituted hydrocarbon residue with a proviso that atleast one of them is a hydrogen atom and (B) 95-5% by weight of apolyamide and (C) 5-100 parts by weight of a copolymer of anethylene-α-olefin copolymer rubber, an alkenyl aromatic compound and anunsaturated carboxylic acid or its anhydride or additionally (D) 0.01-30parts by weight of an epoxy compound based on 100 parts by weight of thecomposition of (A) and (B).

Polyphenylene ether for (A) is a polymer obtained, for example, byoxidation polymerization of one or more of phenol compounds having theformula: ##STR3## wherein R₁, R₂, R₃, R₄ and R₅ which may be identicalor different and represent a hydrogen atom, a halogen atom or ahydrocarbon residue substituted or not and at least one of them is ahydrogen atom, with molecular oxygen or gas containing the same in thepresence of an oxidation coupling catalyst.

Examples of R₁ -R₅ are a hydrogen atom, halogen atoms such as a chlorineatom, a bromine atom, a fluorine atom and an iodine atom, substituted orunsubstituted hydrocarbon residues of 1-18 carbon atoms, for example.alkyl groups or substituted alkyl groups such as a methyl group, anethyl group, an n- or iso-propyl group, a pri.-, sec.- or tert.-butylgroup, a chloroethyl group, a hydroxyethyl group, a phenylethyl group, ahydroxymethyl group, a carboxyethyl group, a methoxycarbonylethyl group,a cyanoethyl group, aryl or substituted aryl groups such as a phenylgroup, a chlorophenyl group, a methylphenyl group, a dimethylphenylgroup an ethylphenyl group, a benzyl group or an allyl group.

Examples of phenol compound are phenol, o-, m- or p-cresol, 2,6-, 2,5-,2,4- or 3,5-dimethylphenol, 2-methyl-6-phenylphenol, 2-6-diphenylphenol,2,6-diethylphenol, 2-methyl-6-ethylphenol, 2,3,5-, 2,3,6- or2,4,6-trimethylphenol, 3-methyl-6-t. butylphenol, thymol and2-methyl-6-allylphenol. Alternatively, copolymer of any of the phenolcompound listed above and the other phenol compound, for example,polyhydroxy aromatic compound, may be employed. The polyhydroxy aromaticcompound is, for example, bisphenol A, tetrabromobisphenol A, resorcin,hydroquinone and novolack resin.

Preferably polymers are homopolymer of 2,6-dimethylphenol or2,6-diphenylphenol and copolymers of a large amount of 2,6-xylenol and asmall amount of 3-methyl-6-t-butylphenol or of 2,3,6-trimethylphenol.

Any oxydation coupling catalyst may be employed for oxidationpolymerization of phenol compound, as long as it has polymerizationability. Examples are cuprous compound/tert. amine such as cuprouschloride/triethylamine and cuprous chloride/pyridine; cupriccompound/amide/alkali metal hydroxide such as cupricchloride/pyridine/potassium hydroxide; manganese salt/primary amine suchas manganese chloride/ethanolamine and manganeseacetate/ethylenediamine; manganese salt/alcolate or phenolate such asmanganese chloride/sodium methylate and manganese chloride/sodiumphenolate; and cobalt salt/tert. amine.

Polymerization temperatures for preparing polyphenylene ether is 40° C.or higher (high temperature polymerization) or lower (low temperaturepolymerization). Either temperature may be used, although polymersproduced thereby have different properties.

Polyphenylene ether for (A) further includes that grafted with styrenicpolymer or other polymer. For instance, grafted one is obtained bygraft-polymerizing styrene monomer and/or other comonomer in thepresence of polyphenylene ether and organic peroxide (Japanese PatentPublications (Kokoku) 47-47862, 48-12197, 49-5623, 52-38596 and52-30991) or by melt-kneading polyphenylene ether and polystyrene in thepresence of a radical initiator (Japanese Patent Publication (Kokai)52-142799).

As the polyamides (B), there may be used those obtained bypolycondensation of lactams of three or more membered rings.polymerizable ω-amino acids, dibasic acids with diamines, etc. Astypical examples thereof, mention may be made of polymers ofε-caprolactam, aminocaproic acid, enantholactam, 7-aminoheptanoic acid,11-aminoundecanoic acid, etc., polymers obtained by polycondensation ofdiamines such as hexamethylenediamine, nonamethylenediamine,undecamethylenediamine, dedecamethylenediamine, m-xylylenediamine, etc.with dicarboxylic acids such as terephthalic acid, isophthalic acid,adipic acid, sebacic acid, dibasic dodecanoic acid, glutaric acid, etc.,or copolymers thereof.

Typical examples of said polyamides are aliphatic polyamides such aspolyamide 6, polyamide 6,6, polyamide 6,10, polyamide 11, polyamide 12,polyamide 6,12, etc. and aromatic polyamides such aspolyhexamethylenediamine terephthalamide, polyhexamethylenediamineisophthalamide, xylene group-containing polyamides, etc. These may alsobe used as mixtures or copolymers of two or more of them.

Mixing ratio of polyphenylene ether (A) and polyamide (B) is suitably5-95% by weight of (A) and 95-5% by weight of (B). When polyamide (B) isless than 5% by weight, solvent resistance and processability are notsufficiently improved and when (B) is more than 95% by weight, thermalproperties such as heat distortion temperature are deteriorated.

The copolymer (C) of ethylene-α-olefin copolymer rubber, alkenylaromatic compound and unsaturated carboxylic acid or its anhydride is acopolymer rubber obtained by allowing an ethylene-α-olefin copolymerrubber to react with an alkenyl aromatic compound and an unsaturatedcarboxylic acid or its anhydride in an organic solvent at 60-150° C. inthe presence of a radical polymerization initiator and in thesubstantial absence of oxygen.

The copolymer (C) of ethylene-α-olefin copolymer rubber, alkenylaromatic compound and unsaturated carboxylic acid or its anhydride isused, since they are well compatible with the composition ofpolyphenylene ether (A) and polyamide (B) and besides have a remarkableeffect of improvement in impact strength. Compatibilization isinsufficient and improvement of impact strength is poor, withoutunsaturated carboxylic acid or its anhydride. Further the use of alkenylaromatic compound in combination prevents reduction of fluidity.Addition amount of the unsaturated carboxylic acid or its anhydride toethylene-α-olefin copolymer rubber is preferably 0.3-5 parts by weight.An amount of unsaturated carboxylic acid or its salt used forpreparation of the copolymer is preferably 0.5-20% by weight ofethylene-α-olefin copolymer rubber and weight ratio of alkenyl aromaticcompound/unsaturated carboxylic acid or its anhydride is preferably0.2-5% by weight.

This modified copolymer rubber is used preferably in an amount of 5-100parts by weight, more preferably in an amount of 10-30 parts by weightfor 100 parts of composition comprising polyphenylene ether (A) andpolyamide (B). When less than 5 parts by weight, improvement of impactresistance is not sufficient and when more than 100 parts by weight,balance between the impact resistance and other properties such as heatresistance is lost.

Ethylene-α-olefin copolymer rubbers are, for example, ethylene-propylenecopolymer rubber, ethylene-butene-1 copolymer rubber,ethylene-propyleneethylidenenorbornene copolymer rubber,ethylene-propylene-dicyclopentadiene copolymer rubber,ethylene-propylene-1,4,-hexadiene copolymer rubber,ethylene-butene-1-ethylidenenorbornene copolymer rubber,ethylene-butene-1-dicyclopentadiene copolymer rubber andethylene-butene-1-1,4-hexadiene copolymer rubber. These modifiedethylene-α-olefin copolymer rubbers may be produced by various methodssuch as solution method, bulk method, etc.

Organic solvents used for the solution method are preferably those inwhich all of said copolymer rubber, unsaturated dicarboxylic acid or itsanhydride and radical polymerization initiator are dissolved at reactiontemperature and, for example, aromatic hydrocarbons such as toluene,xylene and ethylbenzene are preferably used and besides those whichcontain a small amount of polar solvents or aliphatic hydrocarbons suchas acetone, methyl ethyl ketone, terahydrofuran, hexane and heptane mayalso be used.

Reaction temperature which may vary depending on the radicalpolymerization initiator is usually 60-150° C., preferably 70-130° C.Grafting reaction at a reaction temperature of higher than 150° C.causes much gelation of reactants and little product of desiredproperties and that at a temperature lower than 60° C. prevents thegrafting reaction. In the case of bulk method, the desired products mayalso be obtained by melt kneading of styrene, maleic anhydride and aperoxide with an ethylene-α-olefin rubber.

Unsaturated carboxylic acid or its anhydride used for modification is,for example, maleic acid, maleic anhydride, fumaric acid, fumaricanhydride, methylnadic anhydride, dichloromaleic anhydride, acrylicacid, butenoic acid, crotonic acid, vinyl acetic acid, methacrylic acid,pentenoic acid, angelic acid, tiglic acid, 2-pentenoic acid, 3-pentenoicacid, α-ethyl-acrylic acid, β-methylcrotonic acid, 4-pentenoic acid,2-hexenoic acid, 2-methyl-2-pentenoic acid, 3-methyl-2-pentenoic acid,α-ethylcrotonic acid, 2,2-dimethyl-3-butenoic acid, 2-heptenoic acid,2-octenoic acid, 4-decenoic acid, 9-undecenoic acid, 10-undecenoic acid,4-dodecenoic acid, 5-dodecenoic acid, 4-tetradecenoic acid,9-tetradecenoic acid, 9-hexadecenoic acid, 2-octadecenoic acid,9-octadecenoic acid, eicosenoic acid, docosenoic acid, erucic acid,tetracocenoic acid, mycolipenic acid, 2,4-pentadienic acid,2,4-hexadienic acid, diallyl acetic acid, geranic acid, 2,4-decadienicacid, 2,4-dodecadienic acid, 9-12-hexadecadienic acid,9,12-octadecadienic acid, hexadecatrienic acid, linolic acid, linolenicacid, octadecatrienic acid, eicosadienic acid, eicosatrienic acid,eicosatetraenic acid, ricinoleic acid, eleosteric acid, oleic acid,eicosapentaenic acid, erucic acid, docosadienic acid, docosatrienicacid, docosatetraenic acid, docosapentaenic acid, tetracosenoic acid,hexacosenoic acid, hexacodienoic acid, octacosenoic acid, andtetraaconitic acid and anhydrides thereof. Of these compounds,especially preferred is maleic anhydride which is especially high inreactivity.

Styrene is most preferred as alkenyl aromatic compound, buto-methylstyrene, p-methylstyrene, m-methylstyrene, α-methylstyrene mayalso be used. Mixtures of them may also be used.

An amount of alkenyl aromatic compound for 1 part by weight ofunsaturated carboxylic acid or its anhydride is 0.2-5 parts by weight,preferably 0.5-3 parts by weight. When amount of alkenyl aromaticcompound is less than 0.2 part by weight, no effects are seen onprevention of gelation and on increase in amount of grafting reactionand when more than 5 parts by weight, further preferable effects arehardly expected. Total amount of unsaturated carboxylic acid or itsanhydride and alkenyl aromatic compound is 0.5-20% by weight ofethylene-α-olefin copolymer rubber.

The use of a compound containing unsaturated carboxylic acid or itsanhydride is preferable, since compatibility between polyphenylene etherand polyamide is improved and products of good properties are obtained.However, when this compound is introduced into ethylene-α-olefincopolymer rubber, gel is often formed. If products containing gel areused, effects for improvement of properties, especially impact strengthare diminished. It has been found that the use of an alkenyl aromaticcompound in combination therewith results in prevention of formation ofgel and improvement of fluidity when melted. Thus, this invention hasbeen accomplished.

Ethylene-α-olefin copolymer rubber high in content of unsaturatedcarboxylic acid or its anhydride free from gel has markedly superiorproperties and systems in which an alkenyl aromatic compound is furtheradded are better in fluidity when melted than those which contain noalkenyl aromatic compound. These are key points of this invention.

Epoxy compound (D) includes epoxy resin and epoxy group-containingcopolymer. Examples of epoxy resin are bisphenol A epoxy resin, o-cresolnovolac epoxy resin, glycidylamine epoxy resin, three-functional epoxyresin and four-functional epoxy resin. The epoxy compound may furthercontain a reactive diluent.

Epoxy group-containing copolymer includes, for example, unsaturatedepoxy compound/ethylenically unsaturated compound copolymer, epoxidizedpolyester and epoxidized polyamide. Of these copolymers, unsaturatedepoxy compound/ethylenically unsaturated compound copolymer is preferredand especially preferred is a copolymer comprising unsaturated epoxycompound, ethylene and ethylenically unsaturated compound excludingethylene. Unsaturated epoxy compound used for the unsaturated epoxycompound/ethylenically unsaturated compound copolymer has in a moleculeboth an epoxy group and an unsatured group which is copolymerizable withthe ethylenically saturated compound, for instance, unsaturated glycidylester and unsaturated glycidyl ether having the formulas (1) and (2)below: ##STR4## wherein R is a C₂ -C₁₈ hydrocarbon group containingethylenically unsaturated bond and X is --CH₂ --O-- or ##STR5##

Examples are glycidyl acrylate, glycidyl methacrylate, glycidylitaconate, allyglycidyl ether, 2-methylallyl glycidyl ether,styrene-p-glycidyl ether. The ethylenically unsaturated compound isolefin, vinyl ester of C₂ -C₆ saturated carboxylic acid, C₁ -C₈saturated alcohol/acrylic or methacrylic acid ester, meleate,methacrylate, fumarate, halogenated vinyl, styrene, nitrile, vinyl etheror acrylamide. Examples are ethylene, propylene, butene-1, vinylacetate, methyl acrylate, ethyl acrylate, methyl methacrylate, diethylmalate, diethyl fumarate, vinyl chloride, vinylidene chloride, styrene,acrylonitrille, isobutyl vinyl ether and acrylamide. They are usedsingly or in a mixture of at least two of them. Ethylene and vinylacetate are preferable most of all.

Composition ratio of the unsaturated epoxy compound and ethylenicallyunsaturated compound is not critical, but 0.1-50 % by weight, morepreferably 1-30 % by weight of unsaturated epoxy compound is preferred.

The epoxy group-containing copolymer is prepared by various methods.Either random copolymerization or graft copolymerization may beeffected; in the former, unsaturated epoxy compound is introduced inbackbone chain of copolymer, and in the latter, unsaturated epoxycompound is introduced in side chain of copolymer. Examples arecopolymerization in which unsaturated epoxy compound is allowed to reactwith ethylene in the presence of a radical initiator under 500-4000 atm.at 100-300° C. in the presence or absence of a solvent and a chaintransfer agent; graft copolymerization in which polypropylene,unsaturated epoxy compound and a radical initiator are blended andallowed to melt in an extruder; and copolymerization in whichunsaturated epoxy compound is allowed to react with ethylenicallyunsaturated compound in an inert solvent such as water or an organicsolvent in the presence of a radical initiator.

An amount of these epoxy compounds is preferably 0.01-30 parts,preferably 0.01-20 parts by weight per 100 parts by weight of thecomposition of polyphenylene ether and polyamide. When less than 0.01part by weight, the effects of this invention are small and when morethan 30 parts by weight, gelation proceeds to deteriorate moldingprocessability.

Preferred embodiments of this invention may be to use the resincomposition in the form of reinforced composite materials withreinforcing fibers such as glass fiber, carbon fiber, polyamide fiberand metallic whisker and composite materials with addition of inorganicfillers or flame retardants such as silica, alumina, calcium carbonate,talc, mica, carbon black, TiO₂, ZnO and Sb₂ O₃ and furthermore,lubricants, nuclear agents, plasticizers, dyes, pigments, antistaticagents, antioxidants, weatherability providing agents, etc.

Any process is used to prepare the present resin composition.

Melt-blending methods for the components are the best from an economicalpoint of view, although it is possible to blend the components in asolution and evaporate the solvent or precipitate in a non-solvent.Melt-blending is carried out in a single-screw or a twin-screw extruder,a kneader or so, preferably a high-speed twin-screw extruder.

Before kneading, it is preferable to uniformly blend powder or pelletsof the component resins in a tumbler or a Henschel mixer. The firstblending above is not always necessary. Alternatively, each resin may befed to a kneader through a metering apparatus. Resin composition, afterkneaded, is molded according to injection, extrusion and the like.Alternatively, dry blending the resin materials at the injection orextrusion molding without prekneading and direct kneading are made inthe melt processing to produce a shaped article. Any order is used inthe kneading step. For example, compounds for (A) and (B), (C) and (D)are kneaded together, or compounds for (A), (B) and (C) are firstkneaded before (D) is added. However, it is not desirable to kneadcompounds for (C) and (D) and then add compounds for (A) and (B),because gelation occurs and desirable resin composition is not produced.Any other orders may be used for three component system of (A), (B) and(C) or four component system of (A), (B), (C) and (D).

The resin composition of this invention is used as shaped articles,sheets, tubes, films, fibers, laminates, coating materials, etc. made byinjection molding or extrusion molding, especially as automobile partssuch as bumper, inverness, fender, trim, door panel, wheel cover, sideprotector, garnish, trunk lid, bonnet, roof, etc., interior and exteriormaterials and mechanical parts required to have heat resistance.Furthermore, the resin composition is used as parts for motor bicyclessuch as covering material, muffler cover, leg shield, etc. andelectrical and electronic parts such as housing, chassis, connector,base for printed circuit, pulley and other parts required to havestrength and heat resistance.

This invention is explained referring to examples below, wherein theyare merely illustrative ones and this invention is not limited to them.Hardness test, heat distortion temperature test (H.D.T.). Izod impactstrength test (3.2 mm thick) and M.I. are observed in accordance withJIS K7202, JIS K7207, JIS K7110 and JIS K7210, respectively.

Polyphenylene ether, maleic anhydride-grafted ethylene-propylene rubber,maleic anhydride-styrene-grafted ethylene-propylene rubber and epoxycompound used in the examples and comparative examples are obtained inthe following manner. Epoxy resins for the epoxy compound which arecommercially available are used.

1/ Polyphenylene ether

In an autoclave of 10 1 in capacity with jacket which is provided with astirrer, a thermometer, a condenser and an air introducing pipe whichreaches the bottom of the autoclave to make a homogeneous solution, arecharged 3,420 g of xylene, 1,366 g of methanol, 1,222 g (10 mols) of2,6-dimethylphenol and 24 g (0.6 mol) of sodium hydroxide. Thereafter,to the solution is added a solution prepared by dissolving 31.5 g (0.3mol) of diethanolamine, 19.4 g (0.15 mol) of di-n-butylamine and 0.99 g(0.005 mol) of manganese chloride tetrahydrate. Then, while vigorouslystirring the content, air is blown thereinto at a rate of 5 1/min.Reaction temperature and pressure are maintained at 85° C. and 9 kg/cm²,respectively. The supply of air is stopped after lapse of 7 hours fromthe beginning of introduction and the reaction mixture is thrown into amixture of 66 g (1.15 mol) of acetic acid and 4,900 g of methanol. Theresulting slurry is filtered under reduced pressure to isolate wetpolyphenylene ether. The isolated polyphenylene ether is washed with7,200 g of methanol and then dried under reduced pressure at 150° C.overnight to obtain 1,179 g of dried polyphenylene ether, which has areduced viscosity of 0.54 dl/g measured in chloroform of 0.5 g/dl at 25°C.

2 Maleic anhydride-styrene grafted ethylene-propylene copolymer rubber

In a 21 stainless steel autoclave is put 80 g of ESPRENE® E201(ethylene-propylene rubber) or ESPRENE ®E301 (ethylene-propylenenon-conjugated diene rubber; Sumitomo Chemical Co., Ltd.) as anethylene-α-olefin copolymer rubber, and thereto are added 8.0 g ofmaleic anhydride, 8.0 g of styrene and 1,400 ml of toluene. Then, thecontent is purged with nitrogen and then heated to 105° C. with stirringto obtain a homogeneous solution.

Then, to the solution is added 50 ml of a toluene solution containing1.6 g of 1,1-bis(t-butylperoxy) 3,3,5-trimethylcyclohexane and reactionis effected at 105° C. for 1.5 hour with stirring in a nitrogenatmosphere.

After completion of the reaction, to the reaction mixture is added 50 mlof a toluene solution containing 0.8 g of 2,6-di-t-butyl-4-methylphenoland then polymer is precipitated with a large amount of acetone,collected by filtration and dried to obtain a maleic anhydride-modifiedrubber having 3.6% by weight of maleic anhydride grafted and a Mooneyviscosity Ms₁₊₄ 121° C.) of 60.

This modified product is completely dissolved in warm xylene (100° C.)to find no gel formation. In the following examples, amount of maleicanhydride, that of styrene and that of peroxide were suitably changeddepending on Examples and Comparative Examples.

3Maleic anhydride-grafted ethylene-propylene copolymer rubber

This is prepared in the same manner as in the above 2 except thatstyrene is not used. The resulting maleic anhydride-graftedethylene-propylene copolymer rubber has 0.7 % by weight of graftedmaleic anhydride (based on rubber).

4Epoxy compound

Glycidyl methacrylate-ethylene-vinyl acetate copolymer is prepared inaccordance with Japanese Patent Publications (Kokai) 47-23490 and48-113883. That is, 5.9 kg/hr of glycidyl methacrylate, 300 kg/hr ofethylene, 3.4 kg/hr of vinyl acetate, 30 g/hr of a radical initiator,t-butylperoxy-2-ethylhexanoate, and 1.0 g/hr of propylene as achain-transfer agent are successively fed in a reactor (40 1) made ofstainless steel whose temperature is controllable and which is equippedwith an inlet, an outlet and a stirrer and copolymerization is effectedwith stirring under 1400-1600 atm. at 180-200° C. The resulting epoxycompound contains 10% by weight of glycidyl methacrylate, 85% by weightof ethylene and 5% by weight of vinyl acetate.

5Polyamide

Polyamide 6,6: UBE Nylon R 2020B having relative viscosity of 3.0 (UbeIndustries, Ltd.)

Addition amount of maleic anhydride in the modified rubber is obtainedby titration of a toluene solution of the modified rubber with anethanolic KOH solution under heating using phenolphthalein as anindicator.

Addition amount of styrene is determined by making calibration byinfrared analysis using a blend of ethylene-α-olefin rubber and styrene.

EXAMPLE 1

To 100 parts by weight of a resin composition comprising 50 wt% ofpolyamide 6,6 (UBE Nylon R 2020B, relative viscosity 3.0) and 50 wt% ofpolyphenylene ether prepared in the above 1 was added 11.1 part byweight of maleic anhydride-styrene-grafted ethylene-propylene copolymerrubber (modified rubber) prepared by grafting maleic anhydride andstyrene on ESPRENE R E301 (ethylene propylene non-conjugated dienerubber EPDM) prepared in the above 2. This mixture was melted andkneaded at 260° C. in a small batchwise twin-screw kneader("LABOPLASTMIL" R of Toyo Seiki Co.) at a screw rotation of 90 rpm for 5minutes. This modified rubber contained 3.6 wt% of grafted maleicanhydride and 4.0 wt% of grafted styrene on rubber.

The resulting composition was pressed at 280° C. to prepare testspecimen for Izod impact test, heat distortion temperature test andRockwell hardness test. Test results are shown in Table 1.

COMPARATIVE EXAMPLE 1

Example 1 was repeated except that ESPRENE R E301 on which 3.6 wt%(based on rubber) of maleic anhydride was grafted was used as modifiedrubber. This modified rubber was greatly gelled and properties,especially impact strength was inferior. The test results are shown inTable 1.

EXAMPLE 2

Example 1 was repeated except that ESPRENE R E201 (ethylene-propylenerubber EPM) on which 1.6 wt% (based on rubber) of maleic anhydride and2.0 wt% (based on rubber) of sytrene were grafted was used as modifiedrubber. The results are shown in Table 1.

COMPARATIVE EXAMPLE 2

Example 1 was repeated except that ESPRENE R E201 (ethylene-propylenerubber) on which 1.6 wt% (based on rubber) of maleic anhydride wasgrafted was used as modified rubber. The results are shown in Table 1.

These results indicate that in the case of EPDM, when maleic anhydridewas grafted in a large amount, use of maleic anhydride alone causedgelation to deteriorate properties while when styrene was used incombination therewith, no gelation occurred and properties and fluiditywere both superior. In the case of EPM, too, the use of maleic anhydridewith styrene afforded higher heat resistance and better fluidity thanthe use of maleic anhydride without styrene

EXAMPLE 3

Example 2 was repeated except that 2.3 parts by weight of an epoxycompound (glycidyl methacrylate-ethylene copolymer, content of glycidylgroup: 6 wt%) prepared in the above 4 was added to the system used inExample 2. The results are shown in Table 2.

COMPARATIVE EXAMPLE 3

Comparative Example 2 was repeated except that 2.3 parts by weight of anepoxy compound (glycidyl methacrylate-ethylene copolymer, content ofglycidyl group, 6 wt%) was added to the system of Comparative Example 2.The results are shown in Table 2.

The two results also indicate that the use of maleic anhydride withstyrene gave higher fluidity and impact strength than the use of maleicanhydride without styrene.

EXAMPLE 4

Example 2 was repeated except that the maleic anhydride-styrene-graftedEPM was replaced by the EPM on which 0.96 wt% (based on rubber) ofmaleic anhydride and 4.0 wt wt% (based on rubber) of styrene weregrafted. The results are shown in Table 2.

EXAMPLE 5

Example 2 was repeated except that tho maleic anhydride-styrene-graftedEPM was replaced by the EPM on which 1.0 wt% (based on rubber) of maleicanhydride and 1.0 wt% (based on rubber) of styrene were grafted. Theresults are shown in Table 2.

EXAMPLE 6

Example 2 was repeated except that the maleic anhydride-styrene-graftedEPM was replaced by the EPM on which 0.96 wt% (based on rubber) ofmaleic anhydride and 15 wt% (based on rubber) of styrene were grafted.The results are shown in Table 2.

EXAMPLE 7

Example 2 was repeated except that the maleic anhydride-styrene-graftedEPM was replaced by the EPM on which 1.0 wt% (based on rubber) of maleicanhydride and 0.1 wt% (based on rubber) of styrene were grafted. Theresults are shown in Table 2.

                                      TABLE 1                                     __________________________________________________________________________                         C                                                                             Modified ethylene                                                             propylene rubber  Properties                                    A       B     Part by weight                                                                         Addition MI   Izod  H.D.T.                             Polyphenylene                                                                         Polyamide                                                                           per 100 parts                                                                          amount to                                                                              280° C.                                                                     (notched)                                                                           (18.6                                                                                 Rockwellp.2                ether   6,6   by weight of                                                                           rubber (wt %                                                                           10 kg                                                                              Kg    load)   hardness                   wt %    wt %  A + B    based on rubber)                                                                       load cm/cm °C.                                                                            R                   __________________________________________________________________________    Example 1                                                                            50      50    Maleic anhy-                                                                           Maleic                                                                              3.6                                                                              7.8  35.0  171.6   114                                      dride-styrene-                                                                         anhydride                                                            grafted rubber                                                                         Styrene                                                                             4.0                                                              11.1                                                   Comparative                                                                          50      50    Maleic anhy-                                                                           Maleic                                                                              3.6                                                                              Unflow-                                                                            <3.0  127.4   115                 Example 1            dride-grafted                                                                          anhydride                                                                              able                                                        rubber   (gelled)                                                               11.1                                                   Example 2                                                                            50      50    Maleic anhy-                                                                           Maleic                                                                              1.6                                                                              5.3  23.0  152.2   109                                      dride-styrene-                                                                         anhydride                                                            grafted rubber                                                                         Styrene                                                                             2.0                                                              11.1                                                   Comparative                                                                          50      50    Maleic anhy-                                                                           Maleic                                                                              1.6                                                                              1.4  25.3  137.2   113                 Example 2            dride-grafted                                                                          anhydride                                                            rubber                                                                          11.1                                                   __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________                    C                D                                            A           B   Modified ethylene-                                                                             Glycidyl                                                                              Properties                           poly-       poly-                                                                             propylene rubber methacrylate-                                                                         MI                                   phenylene   amide       Addition amount                                                                        ethylene                                                                              280° C.                                                                    Izod  H.D.T. Rockwell            ether       6.6         to rubber (wt %                                                                        copolymer                                                                             10 Kg                                                                             (notched)                                                                           18.6                                                                                 hardnessp.2         wt %        wt %                                                                              Part by weight                                                                        based on rubber)                                                                       Part by weight                                                                        load                                                                              kg · cm/cm                                                                 load                                                                                 Rdegree.C.          __________________________________________________________________________    Example 3                                                                           50    50  Maleic anhy-                                                                          Maleic                                                                              1.6                                                                              2.3     7.6 40.0  136.4  115                                 dride-styrene-                                                                        anhydride                                                             grafted rubber                                                                        Styrene                                                                             2.0                                                               11.1                                                        Compar-                                                                             50    50  Maleic anhy-                                                                          Maleic                                                                              1.6                                                                              2.3     <1.0                                                                              26.4  144.4  112                 ative           dride-grafted                                                                         anhydride                                             Example 3       rubber                                                                          11.1                                                        Example 4                                                                           44.4  55.6                                                                              Maleic anhy-                                                                          Maleic                                                                              0.96                                                                             --      13.6                                                                              19.6  122.8  --                                  dride-styrene-                                                                        anhydride                                                             grafted rubber                                                                        Styrene                                                                             4.0                                                               11.1                                                        Example 5                                                                           44.4  55.6                                                                              Maleic anhy-                                                                          Maleic                                                                              1.0                                                                              --      14.8                                                                              15.8  147.6  --                                  dride-styrene-                                                                        anhydride                                                             grafted rubber                                                                        Styrene                                                                             1.0                                                               11.1                                                        Example 6                                                                           44.4  55.6                                                                              Maleic anhy-                                                                          Maleic                                                                              0.96                                                                             --      14.2                                                                              8.2   157.5  --                                  dride-styrene-                                                                        anhydride                                                             grafted rubber                                                                        Styrene                                                                             15                                                                11.1                                                        Example 7                                                                           44.4  55.6                                                                              Maleic anhy-                                                                          Maleic                                                                              1.0                                                                              --      6.4 10.2  126.4  --                                  dride-styrene-                                                                        anhydride                                                             grafted rubber                                                                        Styrene                                                                             0.1                                                               11.1                                                        __________________________________________________________________________

The resin composition of this invention comprises a composition of apolyphenylene ether and a polyamide with which is blended (a) modifiedrubber (C) obtained by copolymerizing an alkenyl aromatic compound andan unsaturated carboxylic acid or anhydride thereof with anethylene-α-olefin copolymer rubber or (b) the modified rubber (C) withan epoxy compound (D). Although, it has been difficult to improve thebalance of properties and processability by using rubber modified withonly unsaturated carboxylic acid or anhydride thereof, the resincomposition of this invention is improved in properties and is better inprocessability and thus this composition has uses of wide variety.Further, the novel resin composition provided by this invention iseasily processed into shaped articles, sheets and films by moldingmethods employed for thermoplastic resins such as injection molding,extrusion molding, etc., said molded products being very good in balanceof properties such as heat resistance, impact resistance, hardness, etc.This resin composition is especially suitable for injection molding.

We claim:
 1. A thermoplastic resin composition which comprises 100 partsby weight of a composition comprising (A) 5-95% by weight of apolyphenylene ether prepared by oxidation polymerization of at least onephenol compound represented by the formula: ##STR6## wherein R₁, R₂, R₃,R₄ and R₅ which may be identical or different and represent a hydrogenatom, a halogen atom, a substituted or unsubstituted hydrocarbonresidue, with a proviso that at least one of them is a hydrogen atom and(B) 95-5% by weight of a polyamide, 5-100 parts by weight of (C) acopolymer of an ethylene-α-olefin copolymer rubber with an alkenylaromatic compound and an unsaturated carboxylic acid or its anhydride,and 0.01-30 parts by weight of (D) an epoxy compound.
 2. A thermoplasticresin composition according to claim 1 wherein the alkenyl aromaticcompound is styrene.
 3. A thermoplastic resin composition according toclaim 1 wherein the unsaturated carboxylic acid or its anhydride ismaleic anhydride and the alkenyl aromatic compound is styrene.
 4. Athermoplastic resin composition according to claim 1 wherein additionamount of the unsaturated carboxylic acid or its anhydride is 0.3-5% byweight of the ethylene-α-olefin copolymer rubber.
 5. A thermoplasticresin composition according to claim 1 wherein the weight ratio of thealkenyl aromatic compound and to the unsaturated carboxylic acid or itsanhydride is 0.2-5.
 6. A thermoplastic resin composition which comprises100 parts by weight of composition consisting of essentially of (A)5-95% by weight of a polyphenylene ether prepared by oxidationpolymerization of at least one phenyl compound represented by theformula ##STR7## wherein R₁, R₂, R₃, R₄ and R₅, which may be identicalor different, represent a hydrogen atom, a halogen atom, a substitutedor unsubstituted hydrocarbon residue, with a proviso that at least oneof them is a hydrogen atom and (B) 95-5% by weight of a polyamide, 5-100parts by weight of (C) a copolymer of an ethylene-α-olefin copolymerrubber with an alkenyl aromatic compound and an unsaturated carboxylicacid or its anhydride, and 0.01-30 parts by weight (D) an epoxy resin.7. A thermoplastic resin composition according to claim 6, wherein thealkenyl aromatic compound is styrene.
 8. A thermoplastic resincomposition according to claim 6, wherein the unsaturated carboxylicacid or its anhydride is maleic anhydride and the alkenyl aromaticcompound is styrene.
 9. A thermoplastic resin composition according toclaim 6, wherein addition amount of the unsaturated carboxylic acid orits anhydride is 0.3-5% by weight of the ethylene-α-olefin copolymerrubber.
 10. A thermoplastic resin composition according to claim 6,wherein the rate ratio of the alkenyl aromatic compound to theunsaturated carboxylic acid or its anhydride is 0.2-5.
 11. Athermoplastic resin composition which comprises 100 parts by weight of acomposition consisting of (A) 5-95% by weight of a polyphenylene etherprepared by oxidation polymerization of at least one phenyl compoundrepresented by the formula ##STR8## wherein R₁, R₂, R₃, R₄ and R₅, whichmay be identical or different, represent a hydrogen atom, a halogenatom, a substituted or unsubstituted hydrocarbon residue, with a provisothat at least one of them is a hydrogen atom and (B) 95-5% by weight ofa polyamide, 5-100 parts by weight of (C) a copolymer of anethylene-α-olefin copolymer rubber with an alkenyl aromatic compound andan unsaturated carboxylic acid or its anhydride, and 0.01-30 parts byweight (D) an epoxy group-containing copolymer.
 12. A thermoplasticresin composition according to claim 11, wherein the alkenyl aromaticcompound is styrene.
 13. A thermoplastic resin composition according toclaim 12, wherein the unsaturated carboxylic acid or its anhydride ismaleic anhydride and the alkenyl aromatic compound is styrene.
 14. Athermoplastic resin composition according to claim 11, wherein additionamount of the unsaturated carboxylic acid or its anhydride is 0.3-5% byweight of the ethylene-α-olefin copolymer rubber.
 15. A thermoplasticresin composition according to claim 11, wherein the rate ratio of thealkenyl aromatic compound to the unsaturated carboxylic acid or itsanhydride is 0.2-5.